Calendar displayed value not updated on blur

[saithis]

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[ ] feature request => Please check if request is not on the roadmap already https://github.com/primefaces/primeng/wiki/Roadmap
[ ] support request => Please do not submit support request here, instead see http://forum.primefaces.org/viewforum.php?f=35

Plunkr Case (Bug Reports)
Counldn't get the p-calendar to work in plunkr at all, but the bug is also in your demo page:
https://www.primefaces.org/primeng/#/calendar

Current behavior
When you type something that isnt a date like 'asdf' into an empty p-calendar and press tab (or click somewhere else, so the p-calendar input looses focus), then the input isn't cleared.

Expected behavior
The clearing of the input should work.

Minimal reproduction of the problem with instructions

1. open https://www.primefaces.org/primeng/#/calendar
2. type 'asdf' into the Basic p-calendar (the p-calendar mustn't have a value selected before doing this)
3. hit tab
4. 'asdf' doesn't get cleared, as inputFieldValue didn't change

What is the motivation / use case for changing the behavior?
Because it is a bug. Also with the ultima layout the label will then be over the typed in text.

• Angular version: 2.4.X and 4.0.X

• PrimeNG version: 2.0.5 and the one on your demo page

[cagataycivici]

Review for 4.1.0.